Azo dye.



UNTTnD STATES PATENT OFFICE? ADOLF ISRAEL AND RICHARD KOTHE, OF ELBERFELD, GERMANY, ASSIGN- ORS TO FARBENFABRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y.

AZO DYE.

BFE-GIFZUATION forming part of Letters Patent No. 675,629, dated June 4, 1901.

Application filed December 27, 1900.

Serial No. 41,247.

(No specimens.)

We point out specifically that by the term 0 diazo compound in the following specification we intend to denote a simple diazo compound as well as a diazotized amidoazo compound, such as diazoazobenzene, diazoazotoluene, or the like.

The new dyestuffs prepared in the abovedefined manner are alkaline salts of acids having most probably the following general formula:

(in which formula X means an atom of oxygen, which may be replaced by an atom of sulfur, the groups N:NR and N:NR meaning either the same or two difierent radicals of diazo compounds, such as diazobenzene, diazotoluene, diazoazobenzene, acetylamidodiazobenzene, beta-diazonaphthalene, or the like,) and are from reddish-brown to dark-brown powders having a metallic luster soluble in water with from orange to bluishred color, being scarcely soluble in concentrated hydrochloric acid. They dye unmordanted cotton from orange to red shades which are of a remarkable fastness to light.

In carrying out our new process practically we can proceed as follows, the parts being by weight: 17 .6 parts of ortho-anisidin are diazotized in the usual manner with the aid of fiftying diazo solution is then slowly stirred into a solution prepared from 39.2 parts of the sodium salt of carbonyldioxydinaphthylamindisulfonic acid, which is the scientific name of one of the new urea compounds, (prepared from beta -amido-alpha -naphtholbeta sulfonic acid and beta -amido-alpha naphthol-beta -sulfonic acid,) which solution is previously mixed with thirty parts of sodium carbonate. After being stirred for several hours the formation of the dyestuff will be complete. It is then precipitated by the addition of common salt, filtered off, and dried. The new coloring-matter thus obtained is the sodium salt of an acid having most probably the following formula:

and is a reddish-brown powder having a metallic luster soluble in water with a bluish-red color. It is but scarcely soluble in concentrated hydrochloric acid, while'it is dissolved by concentrated sulfuric acid (of 66 Baum) with a violet color, which is changed into blue on the addition of a small quantity of ice, while on the addition of a larger quantity of ice a violet precipitate is obtained.

The new coloring-matter dyes unmordanted cotton bluish-red shades which are fast to acids and to light.

, The process proceeds in an analogous manner if instead of the diazo compound mentioned in the example other diazo compounds are employed. If two different diazo compounds are employed, the first component is Ill X meaning in this formula an atom of oxygen I scarcely soluble in concentrated hydrochloric which may be replaced by an atom of sulfur, the groups -N:NR and N:NR meaning the radicals of diazo compounds and which are from reddish-brown to dark-brown powders having a metallic luster, soluble in water with from orange to bluish-red color,

acid, dyeing unmordanted cotton from orange to red shades which are fast to light, substantially as hereinbefore described.

2. The herein-described new disazo dyestuff being an alkaline salt of-an acid having most probably the following formula:

I OH

which in the form of its sodium salt is a reddish-brown powder having a metallic luster, soluble in water with a bluish red color, scarcely soluble in concentrated hydrochloric acid, being dissolved by concentrated sulfuric acid (of 66 Baum) with a violet color which is changed into blue by the addition of a small quantity of ice, while on the addition of a larger quantity of ice a violet precipitate is obtained, dyeing unmordanted cotton bluish- Ill red shades which are fast to acids and to light, substantially as hereinbefore described.

In testimony whereof We have signed our names in the presence of two subscribing witnesses.

ADOLF ISRAEL. RICHARD KOTHE. WVitnesses:

Or'ro KoNIG, J. A. RITTERSHAUS. 

